1. Wake Forest School of Medicine, Winston-Salem; Alliance Statistics and Data Center, Duke University; Duke University Medical Center, Durham; University of North Carolina Lineberger Comprehensive Cancer Center, Chapel Hill, NC; Alliance Statistics and Data Center, Mayo Clinic, Rochester, MN; Dana Farber Cancer Institute, Boston, MA; City of Hope National Medical Center, Duarte, CA; and Memorial Sloan Kettering Cancer Center, New York, NY